关键词: 发酵, 生物过程, 模型, 参数估值, 碳氮比, 微生物油脂

Abstract:

Microbial lipids, similar to vegetable oil in their composition, are potential alternative feedstock for biodiesel production and oleochemical industries as well. However, the high costs of microbial lipids production are the major bottleneck. The synthesis of microbial lipids is considered as a partially growth-associated process with inconstant production rates. For the prediction of lipid yield and substrate distribution, a chemostat process was established for lipid production by the oleaginous yeast Rhodosporidium toruloides AS 2.1389 under nitrogen limitation conditions, and a correlation on carbon distribution between lipid and lipid-free cell components was also developed. The maximal lipid yield Y_L^maxand cell mass yield Y_L^maxwere predicted to be 0.51 mol C·(mol C)^-1 and 0.52 mol C·(mol C)^-1, respectively. Together with the element balance analysis, the critical C/N ratio for switching to lipid production was estimated to be 12.1 mol·mol^-1. The prediction for lipid yields was 95.2%—116.7% of those measured experimentally, indicating that the model was reliable.

Key words: fermentation, bioprocess, model, parameter estimation, C/N, microbial lipids